Along with practicing monogamy or abstinence, condom use is one of the most effective methods for preventing the spread of HIV/AIDS. However, condom use relies on the agreement and participation of both partners, and in the African context, men typically dominate sexual interactions. Therefore understanding how gender roles and relative power within couples influence male practices of high-risk sexual behaviors, such as inconsistent condom use, engaging in paid sex, or having multiple partners, is essential for countering the spread of the HIV/AIDS across both male and female populations. To better explain this the proposed study will use recent data from the 2004-5 Tanzanian Demographic Health Survey (DHS) to investigate: (1) the effects of individual, household, and relationship characteristics (type and length) on men's sexual risk behaviors (condom use, alcohol use or drunk when have sex), as well as how the effects of relationship characteristics are moderated by (interact with) men's gender attitudes and HIV-risk related attitudes and knowledge; and, (2) how individual, household, relationship, and partners' relative characteristics (age, economic, sexual history, decision-making) influence men's sexual risk behaviors (monogamous, condom use, alcohol use or drunk when have sex, paid sex), as well as how the effects of partners' relative characteristics are moderated by (interact with) men's gender attitudes and HIV-related attitudes and knowledge. The results from the proposed study will help to identify which aspects of gender attitudes and HIV-related attitudes and knowledge are related to men's risky sexual behaviors, and provide information that will inform individual- and couple-level interventions to decrease practices that influence the spread of HIV in sub-Saharan Africa. Understanding the effects of partners' relative power on individual behavior within the context of marriage/ cohabitation will also inform other HIV-related interventions such as adherence to anti-retroviral therapies within families. Overall the proposed study will address a significant gap in the understanding of how gender attitudes and roles in sexual relationships contribute to heterosexual men's HIV-related sexual risk behaviors which will aid in the development of more effective programs to reduce the spread of HIV/AIDS in sub-Saharan Africa. The results from the proposed study will address a significant gap in the understanding of how gender attitudes and roles in sexual relationships contribute to heterosexual men's HIV-related sexual risk behaviors in Tanzania. The study uses information from men and their married/cohabiting partners in order to better understand how relative power within couples influences men's behaviors. This will aid in the development of more effective public health programs to reduce the spread of HIV/AIDS in sub- Saharan Africa. [unreadable] [unreadable] [unreadable] [unreadable]